I actually started out to make a gratin, more in the spirit of our gruyere potatoes, perhaps with a breadcrumb topping. But as I experimented with the recipe, the wonderful flavors of the sweet potatoes and potatoes seemed to get lost in the rich toppings. So the toppings got chucked in favor of a more naked gratin, the un-gratin. The gratin without the gratin part. A rainbow hasselback sweet potato and potato bake. It’s so pretty! I found a big beautiful purple sweet potato at the market that contrasts beautifully with the garnet yam and yellow yukon golds. Sweet potatoes come in many shades, so pick a variety. Going vegan? Swap out the butter in step 3 with olive oil. Then increase the heat to medium high and cook uncovered until golden brown. Remove from heat and stir in salt and thyme. Place the slices in a bowl of water while you are prepping them to prevent them for discoloring. If using purple sweet potatoes, keep the slices in a different bowl of water (the color bleeds). Drain the slices, place them in a bowl. Arrange slices of sweet potatoes and Yukon Gold potatoes in rows on top of the caramelized onions. Brush with melted butter, sprinkle with salt and pepper. Sprinkle with a little more salt and pepper. Garnish with sprigs of fresh thyme. Serve immediately. Gruyere Scalloped Potatoes here on Simply Recipes Sweet Potato Casserole here on Simply Recipes Sweet Potato Roast from Deb Perelman of Smitten Kitchen
